Previously, many types of locks have been used endeavoring to provide an effective means to secure a door and prevent unauthorized access in an institution in a tamperproof manner. In most cases a deadbolt is utilized providing a sliding mechanism that provides a shear action against a strike positioned within a door jamb.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention, however, the following U.S. patents were considered related:
______________________________________ U.S. Pat. No. Inventor Issue Date ______________________________________ 3,743,336 Andrews July 3, 1976 3,081,617 McKay March 19, 1963 2,764,440 Marko Sep. 25, 1956 2,449,353 Whitmore Sep. 14, 1948 1,817,939 Purnell Aug. 11, 1931 ______________________________________
Andrews teaches a pivoting anti-friction rocker arm that is actuated by a spring loaded offset lever arm. Raising a recessed handle moves the lever arm to actuate a sliding bolt in a direction against a spring to disengage the latch. A pivoting rocker arm imparts rectilinear movement to a sliding bolt allowing the bolt to move past the striker.
McKay utilizes a paddle handle hinged on one end having a lock therein with an inwardly projecting tongue extending through a narrow slot. The torque engages a sliding bolt abutment and operates selectively to extend or retract the bolt upon swing movement of the paddle handle. The lock rotates a pawl into a slot within the latch flange impeding its rotary movement.
Marko employs a latch body that is provided with journal bearings in which a pindle is supported on collars of a latch lever engaged so that the lever is free to swing. The lever, further, has an L-shaped arm that reaches into a slot in a bolt guide and moves a sliding bolt against a coil spring to retract the bolt from the device.
Whitmore applies a spring loaded latch bolt that is installed within holes in a housing allowing free linear movement against the spring. A knob attached to a sleeve rotates a latch that is interlocked with the bolt, retracting the bolt when rotated, but allowing free movement to retract when engaged by an angular striker plate.
Finally, Purnell uses a lever to retract a spring loaded bolt that is wedge shaped to prevent rattling. Provided at the outer face of the latch bolt is an antifriction member comprising a roller within a recess in contact with the underside of the bolt adapted to reduce friction between the bolt and the housing.
It can, thus, be seen that prior art has utilized a sliding bolt with an angular end locked into a strike for containment of a door, however, a combination of a latch and a latch bolt with a keyed cylinder and electrical solenoid has not been introduced.